Manufacture of paper tubes



June 24, 1930. w. H. WOODFORD ,7

MANUFQCTURE OF PAPER TUBES Filed July 5, 1927 F1'.7 .E'g.6 g

INVENTOR ix 9 WATSON H. WOOQFRD Patented June 24, 1930 UNITED STATESPATENT OFFICE WATSON H. WOODFORD, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR'I'O REMINGTON ARMS COMPANY, INC., A CORPORATION. OF DELAWARE"-MANUFACTURE OF PAPER TUBES Application filed July 5, 1927. Serial No.208,445.

This invention relates to the manufacture of articles of paper and otherfibrous mate- I rial, and will be described with particular reference tothe manufacture of shot shells, although many aspects of the inventionare applicable to the manufacture of other arti- 0 es In the manufactureof shot shells, tubes for the shell bodies are formed by winding.

starch is usually applied to the surface ofthe paper as it is wound, therolled tubes are then stripped from the mandrel and are subjected tovarious treatments for the purpose of rendering them somewhat imperviousto moisture and also protecting them from burning or charring under theheat generated by the combustion of the shot propellant powder.

The methods hitherto in vogue have involved dipping the tubes in moltenparafiin wax. The paraflin, absorbed by the inner layers of the paper,acted as a heat absorbent, tending to keep thetemperature of the paperbelow its charring point during the firing of the shell, and it alsoacted in a measure to prevent the absorption of moisture. Seriousdisadvantages, however, attend the use of paraflin. The starch adhesiverepels it, so that it was necessary to remove all or nearly all of thestarch applied to the two inner layers of pa er in order to permit theabsorption of a su cient uantity of paraflin to prevent charring. otherdefect arises from the fact that paraflin itself does not render thetubes waterproof. Attempts to apply waterproofing varnishes or lacquershave been unsuccessful owing to the peculiar reaction between paraflinwax and the solvents ordinarily used in spirit varnishes and lacquer.When such a varnish or lacquer is appliedover paraflin wax face. As asmall quantity of the paraflin laden solvent evaporates the precipitatedparaflin forms an impervious film over the wet varnish and preventsfurther evaporat1on of the solvent. If this film is broken, permittingthe solvent to evaporate, the varnish may dry, but the surface issubstanarafiin surface rather than a vartially a nishsur ace.

Other water-proofing agents such as polymerizable oils, have been usedwith a measure of success, but are not entirely satisfactory. One causeof their failure may be found in the fact that the adhesive starchrepels such oils, and it being impracticable to keep the outside of thetube free from starch, only an imperfect and broken coating of thepolymerizable oil can be secured.

It is an object of the present invention to construct a finished articlesuch as a shot shell which will be quite impervious to moisture and willat the same time be proof against any undesirable charring from highheat in its interior.

A further object of the invention is to provide articles such as papertubes for shot shell bodies which while being substantially fire-proofwill have a surface'which is free from greases, waxes and oils.

, A further object of the invention is to provide a paper tube havinginterior layers which are treated with a heat absorbent substance, andother layerswhich are free from said substances.

A further object of the invention is to construct a shot shell capableof receiving a coat of varnish or lacquer.

A- further object of the invention is to devise a method of applyingvarnish, lacquer or other water-proofing medium to the body of the shotshell in such a way as to form a varnish film which is continuous overthe shell body, the crimp and the top wad.

invention consists in the novel devices and methods of procedure,"ofwhich the methods and the devices herein to be described may beconsideredas typical.

In the drawings:

Fig. l is a fragmentary plan view of a sheet of paper prepared forwinding according to the methods of the present invention. I

Fig. 2 is an elevation of a finished shot shell comprising a tube woundfrom paper prepared as illustrated in Fig. 1, the wall of the tube beingbroken in such a way as to show its construction.

Fig-3 is an enlarged section through the wall of a tube wound from sucha sheet of paper as is shown in Fig. 1.

Fig. 4 is a fragmentary sectional view, showing the top wad and crimp ofa shot shell water-proofed in accordance with one method of practicingthe present-invention.

Fig. 5 is a fragmentary plan View of a sheet of paper treated accordingto an alternative method of practicing the invention.

Fig. 6 is an enlarged section through the -Wall of a tube constructedfrom such a sheet as is shown in Fig. 5.

Fig. 7 is an enlarged sectional view of a tube wall modified slightlyfrom Fig. 6.

In order to provide that a part at least of the juxtaposed surfaces ofthe paper in the wound tube shall be free from any substances which willinterfere with the proper action of the adhesive, and that the outer ias to furnish about two complete layers in any substancewhich varnish orlacquer, the tube is protected layer shall be free from will adverselyaffect while at the same time from undesirable and dangerous charring,

the invention contemplates treating a part only of the tube materialwith a heat absorbent substance. This substance, which is convenientlyapplied to the tube forming paper before winding, must be of such anature that it can be applied to the desired part of the aper, whileother parts of the paper are. 1e t and permanently remain free from thesubstance. It must also have a high specific heat thereby enablin it toabsorb such a quantity of heat that t e temperature of the paper willnot be raised to its charring point. It has been found that petrolatumor compositions including'substantial amounts of petrolatum satisfythese requirements.

Fig. 1 illustrates a portion of a sheet prepared for winding by'treating an inter-.

mediate section with petrolatum. A portion 10 of the sheet adjacent oneend and having such a width as to form a little more than one completelayer on the interior of the wound tube is left free from petrolatum.Adjacent to ihis untreated portion 10 is an intermediate section 11,having such a widthv the tube, well impregnated with petrolatum. Theremaining portion 12 of the sheet which forms slightly more than onelayer on the outside of the tube is also left untreated. One side ofthis partof the sheet may be colored if desired according to the usualthe shell comprising the inside untreated.

layer or wrap 10, the intermediate treated layers 11, and the exterioruntreated layer 12. The dry or untreated sections of the paper formingrespectively the inside and outside of the tube each overlap slightlyproviding juxtaposed dry surfaces adjacent the margins of the paperinsuring the adhesion of the margins necessary to prevent unwinding orseparation of the layers. The oil free exterior surface layer 12 isadapted to receive a coating of varnish or lacquer 13.

The properties of the impregnating material as well as the qualities ofthe sheet and the tubes rolled therefrom may be controlled by addingother substances to the petrolatum. For example, penetration of thepaper is increased by the use of about 10% of stearic acid. These andsimilar impregnating materials may obviously be utilized according tothe methods which have been outlined or otherwise in the manufacture oftubes which are wound dry as well as in the making of tubes from sheetsmoistened with starch solution.'

The invention further contemplates waterproofing by the use' of varnish,lacquer or similar materials, and the application of the water-proofingby a method adapted to rapid production, and the packing of the shellswithin a short time after the application of the waterproofing. Thewater-proofing material may be a quickly drying spirit -varnish,pyroxylin lacquer, or pyroxy such varnish or lacquer will, for'thepurpose of this application, be identified as lacquer varnish.

The invention further contemplates the application of the lacquervarnish in such a way as to insure the water-proofing not only of theperiphery of the shell body but also of the top wad and crimp. To thisend, shells are dipped in the lacquer varnish while held in the invertedposition shown in Fig. 2. After dipping, the shells are re-.

tained in the inverted position during drying, the excess lacquervarnish draining from the end of the shell ad'acent the crimp.

In this operation a fillet o lacquer varnish 14 (Fig. 4) is formed inthe angle between the shell crimp 15 and the top wad 16, and retainedthere during the drying by surface tension. By this means the mostvulnerable part of the shell body, namely the joint between the top wadand the crimp is effectively sealed by a heavy and impervious coating.The top wad is coated and waterproofed in the same operation, thelacquer varnish penetrating the wad to a certain extent, as shown inFig. 4. This method of water-proofing is, of course, applicable to anyshot shells or other articles having a surface adapted to receivevarnish, and is not limited to shot shells constructed according to themethods above set forth.

It will be seen that the finished shell is completely sealed byacontinuous coat of varnish which is applied to and dries simultaneouslyon all parts of the shell. A positively water-proof article is thussecured. Shells prepared and treated in this way have been submerged inwater for a period'of 24 hours, and at the end of such period showed noundesirable swelling. Shells water-proofed according tothe best methodshitherto used have been incapable of resisting penetration by moisturewhen submerged for periods of four or five hours. Applicants shells,moreover, are free from undesirable or dangerous charring of the paperduring firing. The interior layer of paper, if untreated, may show localcharring, but the charring is effectively stopped by the treated orcoated layers so that the shell body is not appreciably weakened, andIflO sign of charring reaches the exterior surace.

Figs. 5, 6 and 7 illustrate an alternative form of the invention. Thepaper sheet shown in Fig. 5 has secured to an intermediate sectionthereof a strip of metal foil 110. As shown, the metal foil is of suchwidth as to form one complete layer in the wound tube. In Figs. 5 andG'three layers of paper 100, lie Within the metal foil bearing layer andone layer 120 is placed outside the metal foil. This arrangement,however, may be varied. Thus Fig. 7 shows the metal foil between thesecond and third layers of paper. In either case, the charring of thepaper is positively stop ed b the metal,

p y to the paper from which the tube 1s to be foil, and the tube isentirely free from any greases, waxes or oils having a deleteriouseffect on lacquer varnish. Shot shells comprising tubes made from suchsheets may thus be waterproofed by the application of lacquer varnishaccording to the method above disclosed with excellent results. Thismethod in the manufacture of shot shells has been made the subject of myco-pending ellgspgication Serial #204,845 filed July 11th Therepresentative embodiments and methods of practicing the invention whichhave been described herein are to be considered as illustrative ratherthan restrictive, the invention being susceptible of many modificationsboth as to materials and details of the method of procedure, all fallingwithin the scope of the appended claims:

What is claimed is:

1. In the manufacture of paper shot shells, the method of controlling.charring of the paper under the heat of firing the shell which comprisesthe application of petrolatum to the. shell.

2. The method of making a waterproof and charproof shot shell whichcomprises the application of a heat absorbing material to an interiorportion only of the wall of the shell and the application of lacquervarnish to the exterior of the shell.

3. The method of making a waterproof and charproof shot shell. whichcomprises the application of petrolatum-to a portion of the wall of saidshell, and the application of a lacquer varnish to the exterior of saidwall.

4. A shot shell tube having a portion of its wall impregnated withpetrolatum.

5. A paper shot shell having an interior portion of its wall impregnatedwith petrolatum, and a coating of lacquer varnish upon its exteriorsurface. I

6. In the manufacture of paper tubes for shot shells the method ofprotecting the tube against charring which comprises applying a heatabsorbing material to a portion of the paper from which the tube is tobe wound and then winding the tube.

7, In the manufacture of paper tubes for shot shells the methodof'protecting the tube against charring which comprises applyingpetrolatum to a portion of the paper from which the tube is to be. woundand then winding the tube.

8. The method of making a paper shot shell waterproof and protectedagainst charring which comprises applying a heat absorbing material tothe paper from which the tube is to be wound then winding the tube andthen applying a lacquer varnish to the wound tube.

9. The method of making a paper shot shell waterproof and protectedagainst charring which comprises applying petrolatum Wound then windingthe tube and then applying a lacquer varnish to the wound tube.

10. A wound paper shot shell tube having an intermediate layer of thetube treated with a heat absorbing material, the inner most andoutermost layers of the tube being untreated with said material. y

11. A wound paper shot shell tube having an intermediate layer of thetube treated with petrolatum, the innermost and outermost layers of thetube being untreated with said petrolatum.

12. In a wound aper tube for shot shells the combination 0 petrolatumapplied to an inner wrap of the tube and a waterproofing e tube.

13. A paper shot shell tube protected from charring by petrolatumapplied to an intermediate layer of the tube.

14. A wound paper shot shell tube protected from eharring by at heatabsorbing 5 material applied to an intermediate layer only of the tube.

WATSON H. WOODFORD.

